Steel alloy



Patented Sept. 20, 1932 UNITED STATES P TENT OFFICE FRANZ rorzevrniaor BOCHU1\I,-GERMANY, Assrenon and THE rum nnurscnn EDEL- STAHLWERKE A.-G., or 300mm, GERMANY STEEL ALLOY No Drawing. Application filed April -5, 1929, Serial No. 352,925,- and in Germany May 5, 1928.

Steel alloys are known containing about l to 1.5% carbon, 2 to 8% tungsten, 1% chro mium and 0.5% vanadium. These steels are used among other purposes for turning grooves in chilled iron mill rolls, a process which is called riffeling. For this reason these steels are often called rilfeled steels. They are also used for working in very hard materials such as chilled iron, hard stone,

10 glass or the like, that is, for processes which are carried out at a low cutting speed. In

turning chilled ironthe cutting speed amounts to 0.7 to 1.0 meter per minute. The work is therefore slow and costly.

According to the invention, a great increase in output is attained if the tungsten content is increased to from 10.to 30%, or if,

intead of this, an addition of cobalt is made.

A very great increase of the cutting output is attained if the tungsten content is increased and cobalt is at the same time titled. It has, furthermore, been found that? ith the above tungsten contents thecarbon content can be increased up to 2.5%. .In thefollowing table the cutting output of the new steel alloys are compared with the output of those already known. In all cases chilled iron was worked having a Shore hardness of 80, the crosssection of the shavings being 2 x 0.5 m/m and the cutting speed 4 m. per minute.

Table Composition Lfe lot 0. W0. Cr. V. 00; 00

Minimum 1.5 6.0 1.1 0.5' 7 1. 4 23 1. 1 0. 5 30 v 1.47 6.3 1.0 0.5 10 3O 40 1.4 22 0.7 0.5- 10.4 105 From this table it will be seen that with steels of the character in question tungsten and cobalt are equal as regards their effect. The considerable increase in the cutting speed results in economy, owing to the shorter Working time and the eflicient use of the machines. The alloys described may also be used for purposes in which it is not desired or neces sary to take off shavings. In particular they are suitable for drawing dies or matrices subject to severe strain. Their use is suitable for all purposes where extreme hardness and good wearing qualities are necessary. Chromium and vanadium are not absolutely neces- 5 sary, for obtaining the best values, andother metals such as tungsten, molybdenum and uranium may be added.

The .new steels are characterized by exceptional hardness, which is obtained by quenching in oil or water within a wide range of temperatures.

The present steels have nothing in common with known high speed steels. Known high speed steels are used for working on mate- 5 rials with a large area of cut and high cutting speed. The present steelalloy is, however, specially intended for working on very hard materials which necessitate a comparatively small area ofcut and a low cutting speed.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is 1. A cutting steel alloy comprising approximately 10% to 30% of tungsten, approximately from 10 up to and'including approximately 10.4% of cobalt, small quantities from a trac e to lessthan 1% of chromium, from 1.4% to lessthan 2.5% of carbon 3 and the balance substantially all iron, excepting small quantities of impurities and small quantities of other elements commonly present in steels of this type in amounts not great or than 2% in the aggregate. y I

2. A cutting steel alloy comprising approximately 10% to, 30% of'tungsten, approximately from 10 up toand including approximately 10.4% of cobalt, small quantities from a trace to less than 1%.of chromium, from 1.41% to less than 2.5% of carbon and the balance substantially all iron, excepting small quantities of impurities and approximately 0.5% of vanadium.

3. A cutting steel alloy comprising. a

proximately 22% of tungsten, approximate y 10.4% of cobalt, approximately 0.7% of chromium; 1.4% of carbon, 0.5% of vanadium and the balance substantially all iron.

In testimony whereof I aflix my signature.

FRANZ PoLzGUTER. 

